221101021 has 4 divisors (see below), whose sum is σ = 228233344. Its totient is φ = 213968700.

The previous prime is 221101007. The next prime is 221101039. The reversal of 221101021 is 120101122.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 221101021 - 2⁵ = 221100989 is a prime.

It is a super-2 number, since 2×221101021² = 97771322974484882, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 221100989 and 221101007.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221101061) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3566115 + ... + 3566176.

It is an arithmetic number, because the mean of its divisors is an integer number (57058336).

Almost surely, 2^221101021 is an apocalyptic number.

It is an amenable number.

221101021 is a deficient number, since it is larger than the sum of its proper divisors (7132323).

221101021 is an equidigital number, since it uses as much as digits as its factorization.

221101021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7132322.

The product of its (nonzero) digits is 8, while the sum is 10.

The square root of 221101021 is about 14869.4660630434. The cubic root of 221101021 is about 604.6864673281.

Adding to 221101021 its reverse (120101122), we get a palindrome (341202143).

The spelling of 221101021 in words is "two hundred twenty-one million, one hundred one thousand, twenty-one".